1 // Copyright 2017 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 // The output should warn when a loop label is not used. However, it
12 // should also deal with the edge cases where a label is shadowed,
13 // within nested loops
17 #![feature(label_break_value)]
18 #![warn(unused_labels)]
21 'unused_while_label: while 0 == 0 {
22 //~^ WARN unused label
26 'unused_while_let_label: while let Some(_) = opt {
27 //~^ WARN unused label
30 'unused_for_label: for _ in 0..10 {
31 //~^ WARN unused label
34 'used_loop_label: loop {
35 break 'used_loop_label;
38 'used_loop_label_outer_1: for _ in 0..10 {
39 'used_loop_label_inner_1: for _ in 0..10 {
40 break 'used_loop_label_inner_1;
42 break 'used_loop_label_outer_1;
45 'used_loop_label_outer_2: for _ in 0..10 {
46 'unused_loop_label_inner_2: for _ in 0..10 {
47 //~^ WARN unused label
48 break 'used_loop_label_outer_2;
52 'unused_loop_label_outer_3: for _ in 0..10 {
53 //~^ WARN unused label
54 'used_loop_label_inner_3: for _ in 0..10 {
55 break 'used_loop_label_inner_3;
59 // You should be able to break the same label many times
68 // Test breaking many times with the same inner label doesn't break the
69 // warning on the outer label
70 'many_used_shadowed: for _ in 0..10 {
71 //~^ WARN unused label
72 'many_used_shadowed: for _ in 0..10 {
73 //~^ WARN label name `'many_used_shadowed` shadows a label name that is already in scope
75 break 'many_used_shadowed;
77 break 'many_used_shadowed;
82 'unused_loop_label: loop {
83 //~^ WARN unused label
87 // Make sure unused block labels give warnings...
88 'unused_block_label: {
89 //~^ WARN unused label
92 // ...and that used ones don't:
94 break 'used_block_label;